• Visual Studio 2019 16.10 Preview 2 がリリース
• 追加された C++20 関連の新機能
  • <source_location>
  • <syncstream>
  • constexpr std::vector
  • constexpr std::string
  • C++20 Ranges の完成
• C++20 完全実装まであと少し（現在 95% ぐらい）
• 上記の新機能を試せるサンプルコード:

# include <iostream>
# include <string>
# include <source_location>
# include <syncstream>
# include <ranges>
# include <vector>
# include <future>
# include <algorithm>
# include <numeric>
void F()
{    // ソースコードのファイル名、関数名、行番号、列番号取得
    constexpr auto sl = std::source_location::current();
    std::cout << "File: " << sl.file_name() << '\n'
              << "Function: " << sl.function_name() << " ("
              << sl.line() << ", " << sl.column() << ")\n";
}
constexpr int Sum() // std::vector を使っても constexpr に
{
    std::vector<int> v;
    for (int i = 0; i <= 10; ++i)
    {
        v.push_back(i);
    }
    return std::reduce(v.begin(), v.end());
}
int main()
{
    static_assert(Sum() == 55);
    static_assert(std::string("Hello").size() == 5);
    F();
    std::cout << "--------------\n";
    for (int i : std::views::iota(0, 5))
    {
        std::cout << i << '\n';
    }
    std::cout << "--------------\n";
    {
        std::vector<std::future<void>> v;
        for (int i = 0; i < 5; ++i)
        {
            v.push_back(std::async(std::launch::async, [=]() {
                // 標準出力を排他制御。出力が混在しなくなる
                std::osyncstream{ std::cout } << "Hello, " << i << '\n'; }));
        }
    }
    std::cout << "--------------\n";
    {
        std::vector<std::future<void>> v;
        for (int i = 0; i < 5; ++i)
        {
            v.push_back(std::async(std::launch::async, [=]() {
                std::cout << "Hello, " << i << std::endl; }));
        }
    }
}